AF Patient Perspective: A Small Comparative Study on Catheter vs. Surgical Ablation

AF Patient Perspectives' Blog by: Steve S. Ryan is the founder of A-Fib.com, a website designed primarily for non-medical personnel and written from a patient's point of view. Steve had atrial fibrillation (A-Fib) and was cured in April 1998 by pulmonary vein ablation isolation. Steve is not a medical doctor (though he does have his PhD from Ohio State University). He is also author of the book Beat Your A-Fib: The Essential Guide to Finding Your Cure. There have been several multi-center studies about the efficacy and safety of catheter ablation, but few about the newer surgical ablation (Mini-Maze). Perhaps for the first time, a recent small study compared the two treatments head-to-head. The ‘FAST' study was funded by AtriCure, Inc., maker of the AtriCure Synergy Ablation System used in the study (FDA approved December 2011). Description of study: Fifty-nine patients at St. Antonius Hospital in Nieuwegein, the Netherlands and 64 patients at Hospital Clinic in Barcelona, Spain were randomized to receive either a catheter ablation (CA) or surgical ablation (SA). Patients were selected who had a prior failed catheter ablation (67%), had a left atrium diameter of 40 to 44 mm and hypertension, or a left atrium diameter greater than 45 mm (33%). At St. Antonius Hospital, the pulmonary veins were re-isolated. No additional lines or ablation strategies were performed regardless of the type of A-Fib. A non-irrigated tip RF catheter was used. (This is surprising to me, as irrigated-tip catheters are considered the standard of practice at most centers.) Hospital Clinic used an irrigated tip RF catheter. At the discretion of the operator were an additional left atrium roofline and/or a mitral isthmus line. Neither site mentioned using current mapping strategies to isolate activation sites, or use of Complex Fractionated Atrial Electrograms, Dominant Frequency, or step-wise ablation protocols. The study authors did note that "patients in the CA group may have been undertreated compared with patients in the SA group."(1) "More than 40% of (the CA) patients had nonparoxysmal AF and may have been undertreated by PVI alone...67% had already failed a prior CA, which may be a more serious predisposition to failure than anticipated."(1) The surgical ablations used the AtriCure Synergy Ablation System (an RF clamp) to ablate and isolate the pulmonary veins. In addition, 31% of patients had various LA ablation lines at the LA roof, aortic trigone, mitral isthmus, or box lesion around the PVs. "Part of these lines were made...without verifying that conduction block had indeed been established."(1) (The authors concluded "efficacy tended to be a little lower in patients with such lines."[1]) The left atrial appendage was also removed, and ganglia areas on the outside of the heart were ablated. Remarkably, the authors state, "So far, no randomized clinical trials have quantified the added effect of surgical ganglia ablation to achieve freedom from AF."(1) The study results: The CA efficacy was low at 44.4% (one reason may be the limited choice of ablation strategies). The SA efficacy was 67.2%, lower than the over 90% success rates often reported (in unpublished, self-reported, or single-center, non-controlled series with short duration and follow-up). This is all the more surprising because the surgical arm, in addition to isolating the pulmonary veins, often employed additional extensive lesion sets and burns in the left atrium and elsewhere on the heart. The procedural adverse event rate for the SA patients was 23% (approximately 1 out of 4 patients), which was significantly higher than the 3.2% rate for CA patients. The main procedural complications in surgery were pneumothorax (collapsed lung), major bleeding, and the need for a pacemaker. These complications were caused "mostly from direct mechanical injury during the procedure. About half required additional intervention and/or prolonged hospitalization." These "events reported with CA seemed more transient and did not require any intervention."(1) They seemed to center around anticoagulation, with bleeding on the one hand and transient ischemic attack, stroke and hemorrhage stroke on the other. (One of the CA patients died of a hemorrhagic stroke a month after the ablation.) CA procedure time was faster, on average 163 minutes versus a SA average of 188 minutes. CA patients stayed in the hospital 2.0 days, versus 5.5 days for surgery. Interpreting the data: Though not the fault of study investigators, the deck seemed stacked against catheter ablation. Doctors were limited in the ablation strategies they could use. At one site doctors could only re-isolate pulmonary veins using a non-irrigated catheter, which is considered outdated and less effective. The study selected patients (67%) who had failed a previous PVI, then excluded ablation strategies commonly used in such cases. The success rates were far lower than in previously published and documented studies. But what was more surprising was the lower-than-expected 67.2% success rate for the surgical arm, which seemed to use the newest, most advanced extensive lesion sets and burns to achieve success. This was probably the first study to provide documented, verifiable, non-self-reporting data on the safety of surgical ablation (Mini-Maze). The results for SA patients were not good. A 1-in-4 chance of an adverse event is not acceptable for most SA patients. While this study did not address simpler cases of paroxysmal A-Fib, the SA operations are generally the same or ‘one-size-fits-all’ for paroxysmal as for more complex cases. One of the more disturbing SA findings regards the efficacy of extensive ablation lines and burns. With the more advanced surgical approaches using ablation lines on the left atrium and burns on other areas of the heart, "efficacy tended to be a little lower in patients with such lines." Extensive ablation lines and burns didn't seem to improve SA results, at least in this study. The FAST study was relatively small. A-Fib patients shouldn't rely entirely on the results of this study for their medical decisions. But while the efficacy results for catheter ablation should probably be discounted because of design bias, I believe the study does raise some red flags particularly about the high procedural adverse event rate and safety of surgical ablation (Mini-Maze) operations. Most reports of the FAST study tout the higher success rate of surgical versus catheter ablation, but these results don’t hold up on close scrutiny. More important for patients is the high complication rate of surgical ablation. Reference 1. Boersma LV, et al. Atrial Fibrillation Catheter Ablation Versus Surgical Ablation Treatment (FAST): A 2-Center Randomized Clinical Trial. Circulation 2012 Jan 3;125(1):23-30. Epub 2011 Nov 14. Dr. Steve Ryan, PhD, is a healthcare educator and advocate for patients with Atrial Fibrillation. He is publisher of the website, Atrial Fibrillation: Resources for Patients (www.A Fib.com), and author of the new book, Beat Your A-Fib: The Essential Guide to Finding Your Cure (www.BeatYourA-Fib.com). Email him at ssryan@A-Fib.com.